The present invention relates in general to a pack cosmetic, and more particularly to a peel-off emulsion-type pack cosmetic which exhibits a shorter drying time after application of the pack and superior usability.
A pack cosmetic is widely used for the purpose of moisture retention and cleaning of the skin. There are several types according to how they are used including the peel-off type, wipe-off or rinse-off type, and pasting type.
Of these, the peel-off type, which is applied on the skin, dried to form a film, and then peeled off, is used a great deal because it exhibits the superior effect of removing smudges on the skin surface, old corneum, black stains on the pores, and keratotic plugs, and gives a high level of satisfaction at the time of use.
However, the peel-off type pack cosmetic has a shortcoming in that the let-stand time (or drying time) after application is long. A single use usually takes about 30 minutes, which is a hindrance to the use of a pack cosmetic in busy daily life. Because of this, several attempts to make the drying time shorter than the conventional duration have been made. For example, the drying time can be shortened by increasing the alcohol content in the formulation. However, in this case, there is a problem in that a higher alcohol concentration stimulates the skin and/or eyes and such. The drying time can also be shortened by, for example, blending in a large amount of powder and such to reduce the amount of water in the formulation, or adding a substance which interacts with the film agent to form a gel to promote the film formation during the drying time. However, each of these cases have a problem in terms of stability because, for example, the product in storage hardens over time due to gelation. As described thus far, it has been difficult to obtain a peel-off type pack cosmetic which has a short drying time and is free of problems as a product.
In light of the aforementioned situation, the inventors conducted earnest research to obtain a fast drying pack cosmetic which has a short drying time and is free of problems as a product, and, amazingly, discovered that a peel-off type pack cosmetic with a short drying time and superior usability with very smooth peeling can be obtained as an emulsion-type pack cosmetic containing polyvinyl alcohol, oil, and water if the oil content is adjusted to 20-80 wt % or 15-50 wt % of the total emulsion-type pack cosmetic and, preferably, a surfactant is contained as well, thus completing the present invention.
The object of the present invention is provide a fast-drying peel-off type pack cosmetic which has a short drying time and superior usability.
That is, the present invention provides an emulsion-type pack cosmetic containing polyvinyl alcohol, oil, and water which characteristically contains the oil in the amount of 20-80 wt % of the total emulsion-type pack cosmetic.
Also, the present invention provides an emulsion-type pack cosmetic containing polyvinyl alcohol, oil, and water which characteristically contains the oil in the amount of 15-50 wt % of the total emulsion-type pack cosmetic.
Furthermore, the present invention provides an emulsion-type pack cosmetic containing polyvinyl alcohol, oil, and water which characteristically contains the oil in the amount of 25-40 wt % of the total emulsion-type pack cosmetic.
Also, the present invention provides said emulsion-type pack cosmetic which additionally contains a surfactant.
Furthermore, the present invention provides said emulsion-type pack cosmetic wherein the content of said surfactant is 1-20 wt % of the total emulsion-type pack cosmetic.
The configuration of the present invention is described in detail below.
The polyvinyl alcohol used in the present invention functions as a film agent and emulsifying agent of the emulsion-type pack cosmetic, and its selection is not limited as long as it acts as a film agent and emulsifying agent. A commercially available polyvinyl alcohol, for example, can be used.
Commercially available polyvinyl alcohols are divided into several grades based on differences in the degree of polymerization and the degree of saponification. The degree of polymerization is usually indicated by the viscosity measurement of a 4%-concentration aqueous solution at 20xc2x0 C. For the present invention, those with a low viscosity of 4 cps to a high viscosity of 70 cps can be used. However, the formed film tends to become stronger and the viscosity of the pack increases as the degree of polymerization becomes higher. Therefore, considering the adequate strength of the film and the viscosity which makes pack application easy, it is preferable to use polyvinyl alcohol in the viscosity range of 30-50 cps.
On the other hand, the degree of saponification is defined based on different saponification ratios of the acetyl groups in polyvinyl acetate when manufacturing polyvinyl alcohols, which is largely divided into the complete saponification type which is saponified almost completely (98-100%), and xe2x80x9cthe partial saponification typexe2x80x9d, which is partially saponified (87-89%) with some remaining acetyl groups. Although both saponification types can be used in the present invention, the partial saponification type has a higher solubility at room temperature, better viscosity stability at lower temperatures, and a superior ability to emulsify the blended oil, and therefore it is preferable to use the partial saponification type polyvinyl alcohol.
The blend ratio of the aforementioned polyvinyl alcohol is preferably 5-20 wt %, more preferably 9-15 wt %, of the total amount of the pack cosmetic. If the blend ratio is less than 5 wt %, then a film with adequate strength will not form and even peeling will be difficult. On the other hand, if the blend ratio is more than 20 wt %, then the viscosity will be too high and application may not be easy.
The oil used in the present invention is not limited in particular, and any oil which is used in emulsified cosmetics can be used. Examples include natural animal/plant oils/fats such as macademia nut oil, evening primrose oil, olive oil, mink oil, jojoba oil, lanolin, and squalene; hydrocarbons such as liquid petrolatum, squalane, and petrolatum; higher alcohols such as cetanol, stearyl alcohol, and cetyl alcohol; higher fatty acids such as myristic acid, palmitic acid, stearic acid, behenic acid, isostearic acid, oleic acid, linolic acid, linolenic acid, and oxystearic acid; esters such as pentaerythritol tetra 2-ethylhexanoate, isopropylmyristic acid, isopropylpalmitic acid, isopropylstearic acid, and glyceryl 2-ethylhexanoate; diorgano polysiloxanes with low to high viscosity such as dimethyl polysiloxane, methylphenyl polysiloxane, methylhydrogen polysiloxane and dimethyl siloxane/methylphenyl polysiloxane copolymer, cyclic siloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and tetramethyltetraphenyltetracyclosiloxane, cyclic siloxane solutions such as high polymer gum-like dimethyl polysiloxane, gum-like dimethylsiloxane/methylphenylsiloxane copolymer and gum-like dimethyl polysiloxane, diorgano polysiloxane containing alkyl groups with a carbon number of 6-50, and silicone oils such as amino modified silicone, alkylated silicone and fluorine modified silicone. One or more of these oils can be blended in. Using volatile silicone oil is preferable in terms of the sensation at the time of application. It is also possible to give a moist feeling to the skin after peeling by adding natural animal/plant oils/fats.
The blend ratio of the oil is 20-80 wt % or 15-50 wt % of the total amount of the emulsion-type pack cosmetic. If it is less than 15 wt % then the fast drying effect will be poor, and blending more than 50 wt % or 80 wt % results in a high viscosity, sometimes causing a problem in terms of usability at the time of application. From the usability point of view in particular, 25-40 wt % is preferable. Water which is used in the present invention is stirred and mixed with the aforementioned essential ingredients to form an emulsified composition, from which the emulsion-type pack cosmetic of the present invention can be manufactured with a conventional method. The blend ratio of water is not limited in particular, but usually 30-60 wt % of the total amount of the emulsion-type pack cosmetic is preferable. As the blend ratio of the oil increases, the water content decreases in comparison. However, there is no difference in the water evaporation rates of the pack cosmetics with various blend ratios, which indicates that the fast drying properties due to blending of the oil is not related to the water content.
In the present invention, it is preferable to additionally blend in a surfactant. The addition of a surfactant to the emulsion-type pack cosmetic of the aforementioned composition has a significant effect in terms of the drying time and usability.
The selection of the surfactant for use in the present invention is not limited in particular. Nonionic surfactants (hydrophilic or lipophilic) are preferable. Specific examples include POE-sorbitan fatty acid esters including POE-sorbitan monooleate, POE-sorbitan monostearate, POE-sorbitan monooleate and POE-sorbitan tetraoleate, POE-sorbitol fatty acid esters including POE-sorbitol monolaurate, POE-sorbitol monooleate, POE-sorbitol pentaoleate and POE-sorbitol monostearate, POE-glycerol fatty acid esters including POE-glyceryl monostearate, POE-glyceryl monoisostearate and POE-glyceryl triisostearate, POE-fatty acid esters including POE-monooleate, POE-distearate, POE-monodioleate and ethylene glycol distearate; POE-alkyl ethers including POE-lauryl ether, POE-oleyl ether, POE-stearyl ether, POE-behenyl ether, POE2-octyldodecyl ether and POE-cholestanol ether, pluaronics including pluronic, POE-POP alkyl ethers including POE-POP cetyl ether, POE-POP2-decyltetradecyl ether, POE-POP monobutyl ether, POE-POP lanolin hydrate and POE-POP glycerol ether, tetra POE-tetra POP ethylenediamine condensates including tetronic, POE-castor oil hydrogenated castor oil derivatives including POE-castor oil, POE-hydrogenated castor oil, POE-hydrogenated castor oil monoisostearate, POE-hydrogenated castor oil triisostearate, POE-hydrogenated castor oil monopyroglutamate monoisostearate, POE-hydrogenated castor oil maleate, POE beeswax/lanolin derivatives including POE sorbitol beeswax, alkanol amides including coconut fatty acid diethanol amide, lauric acid monoethanol amide and fatty acid isopropanol amide; as well as POE-propylene glycol fatty acid ester, POE-alkyl amine, POE-fatty acid amide, sucrose fatty acid ester, POE nonylphenylformaldehyde condensate, alkylethoxydimethylamine oxide and trioleyl phosphate.
The blend ratio of the surfactant is not limited in particular. A preferable blend ratio range is 1-20 wt %, more preferably 3-10 wt %, of the total amount of the emulsion-type pack cosmetic. If the blend ratio is less than 1 wt % then the improvement in the usability and drying time may not be easily attained. If it is more than 20 wt %, then the viscosity becomes too high and the usability may be affected.
Although an emulsion-type pack cosmetic containing polyvinyl alcohol, oil, and water is prior art, the conventional emulsion-type pack cosmetic has an oil content of approximately 10 wt % or less, and there is no case where 15 wt % or more oil is blended in. An emulsion-type pack cosmetic which has an oil content of 15 wt % or more and also contains a surfactant is new also as an emulsified composition for cosmetics, and the present invention is the first case which uses said emulsified composition for a cosmetic.
In addition to the aforementioned essential ingredients, ingredients which are normally blended into cosmetics can be blended in the pack cosmetic of the present invention as necessary within the range that does not affect the effect of the present invention. Examples of ingredients which can be blended in include lower alcohols such as ethanol and isopropyl alcohol, polyhydric alcohols such as glycerine, propylene glycol, dipropylene glycol, 1,3-butanediol, sorbitol, and maltitol, powders such as talc, kaolin, titanium oxide, and silicic acid anhydride, water soluble polymers such as polyvinyl pyrolidone, polyvinyl acetate, carboxymethyl cellulose, and xanthan gum, preservatives, disinfectants, ultraviolet light absorbents, chelating agents, antioxidants, and perfumes.